1. Field of the invention
Various aspects of the present invention relate to game rackets used for striking an object. Specifically in some implementations, game rackets and inflation bladder methods for making said game rackets, such that the game rackets are stronger, lighter, and more useful in general than conventional game rackets.
2. Description of Related Art
Conventional composite racket frames made by the inflation bladder molding method are typically made with a single bladder surrounded by composite pre-preg material, then placed in a mold cavity for final formation. This relatively simple process has become the industry standard. A racket made by this method, while lightweight and strong, does have sonic drawbacks. The hollow frame leads to a profile that is unstable due to torsion. In addition, the frame lacks compressive strength along the axis of the string-bed plane, i.e. a hollow racket frame can be designed to resist bending due to use, but its compressive resistance to forces such string tension and impact shock is inherently limited. This type of frame also typically requires drilling of string holes in a straight line around the head frame after molding, resulting in an even weaker frame.
U.S. Pat. Nos. 6,071,203 and 6,800,239 concern molding techniques that utilize two bladders wrapped with pre-preg material to make one complete unitary racket profile. In these rackets, string holes can be pre-formed in the racket fabrication process, thus eliminating the need for drilling; string hole openings may also be “ports,” with a bearing structure that strengthens the frame. In addition, the continuous internal wall of the frame profile increases overall strength. Frames developed by this method, however, are not without significant drawbacks. Pre-formed string holes or ports are labor intensive and require human intervention to achieve the design.
This limitation was addressed in U.S. Pat. No. 7,396,303, where applicants replaced preformed string holes with “cutouts” or elongated openings with a separately made plastic bearing for the strings. This design does reduce the labor required, but also compromises the torsional stability and compressive strength of the frame profile—thus significantly weakening the frame. To compensate, the frame is then in need of a stabilizing mechanism.
So as to reduce the complexity and length of the Detailed Specification, and to fully establish the state of the art in certain areas of technology, Applicant(s) herein expressly incorporate(s) by reference all of the following materials identified in each numbered paragraph below.
U.S. Pat. No. 6,071,203
U.S. Pat. No. 6,800,239
U.S. Pat. No. 7,396,303
U.S. application Ser. No. 13046723
Applicant(s) believe(s) that the material incorporated above is “non-essential” in accordance with 37 CFR 1.57, because it is referred to for purposes of indicating the background of the invention or illustrating the state of the art. However, if the Examiner believes that any of the above-incorporated material constitutes “essential material” within the meaning of 37 CFR 1.57(c)(1)-(3), applicant(s) will amend the specification to expressly recite the essential material that is incorporated by reference as allowed by the applicable rules.